In a conventional I.S. glassware forming machine, glassware forming moulds are cooled by blowing air at the outer surfaces of the moulds. However, it has been found that this method of cooling is difficult to control and is extremely noisy. In more refined systems, air has been ducted to the moulds and has been discharged at the mould surfaces from short-range, i.e. from a distance of 1 inch or less. Although such systems show a slightly improved efficiency and slight reductions in noise levels, the noise levels are still very high. Water cooling has been tried in an effort to overcome the problem of noise, but although water cooling is almost completely silent, cooling has been found to be too severe and attempts to reduce the cooling by reducing the rate of flow of the cooling water have resulted in boiling of the water and loss of control. Hence, water cooling is limited in practice to the cooling of items such as press plungers.